Well, I can share my "procedure" at least. I would suggest using whatever recipe is your favorite, that you feel most comfortable with. You probably don't want to try a "new" recipe with this one, since there are a few minor added challenges involved.
First, I cooked a small portion of plain oatmeal on the stove top. I took that, added some extra water, and blended it to liquid in my Vitamix (blender). I measured that out to be my liquid portion.
Another prep to do is to make oat "flour". I took old-fashioned oats and put them in my blender and blended until they were as fine as flour/powder. Set that aside for later.
Also, get a bowl of regular, dry old-fashioned oats ready for the topping.
Okay.....so you'll SLOWLY mix the lye into the oat liquid/puree and stir a LOT. (I should have frozen this oat liquid first, but didn't, and it got HOT!!). It takes a good bit of focused stirring, but I did it for awhile to make sure all the lye was incorporated. I had to add a tad bit extra water to the mixture too.
So then pour the lye "milk"/goop/paste into the oils and blend it in. Slowly sprinkle the oat "flour" into the soap and blend it in a bit at a time so it doesn't clump. Then pour into mold and top with whole oats.
I think I used 2-3 tsp. oat flour PPO. I need to double check my notes, but I know it was a good bit, since the guy wanted a heavily oated soap.
I might have forgotten some details, so just ask